New satellite capabilities target UAV needs

As the Defense Department’s use of unmanned aerial vehicles (UAVs) continues to skyrocket, the UAVs' reliance on satellite communications links will remain a key part of the uplink and downlink bandwidth consumed by the military. A panel of satellite industry experts discussed how new communications technologies will influence both UAVs and the commercial market’s ability to support the DOD at the Satellite 2012 conference in Washington on March 13.

New types of commercial satellites entering service have greatly increased bandwidth and are equipped with spot beams capable of supporting many users across a region, said Barry Jackson, CEO of Cahon Systems. Spacecraft such as Inmarsat’s Global Express will offer downlink capacities of 50 Mbps and uplink speeds of 5 Mbps, he said. Additionally, Irridium’s new constellation of low Earth orbit communications satellites will soon be coming online to provide additional capability, he said.

In the near future, new developments in waveforms will allow new types of UAVs to enter service, Jackson said. The new types of high-capacity waveforms will be able to operate on unmanned helicopters. This is problematic because the aircraft’s rotating blades interfere with older waveform types, he said.

A key trend in the area is the development of open standards based waveforms for use by UAVs, said Mark Dale, vice president of product management at Comtech EF Data. One of these waveforms is DVB-S2, which is used in point-to-point modems, broadcasting and time division multiple access communications. The waveform is ideal for UAV applications because it has good performance when transmitted from the small antennas commonly found on airborne platforms and for its ability to support adaptive coding and modulation standards, he said.

The move to new waveforms is important because many unmanned aircraft use older technology that does not have the best performance capabilities, Dale said. The Air Force is considering using DVB-S2-based systems for its future UAV programs, he added.

Protecting UAV's satellite communications links also will be an important challenge in the future, said Stuart Linsky, vice president of communications systems at Northrop Grumman. Where it once took an advanced nation state to jam U.S. military communications, new ubiquitous technologies now expose unmanned systems to jamming and cyberattacks. “The ease with which the bad guys can do bad things has gotten easier,” he said.

Over the last 12 years, the U.S. government has spent billions of dollars on communication technology, Linksy said. Many of these systems are far more advanced than commercial technology in their ability to resist and jamming and operate in difficult radio frequency environments. These capabilities can be used for protected wideband relays for UAVs, especially if they are transmitted from wideband phased array antennas that will soon be entering service on the next generation of military communications satellites, he said.